The so-called intact PTH is the most frequently ordered parathyroid hormone test. It is used to help diagnose the cause of a low or high calcium level and to help distinguish between parathyroid-related and non-parathyroid-related causes. It may also be used to monitor the effectiveness of treatment when an individual has a parathyroid-related condition. PTH is routinely monitored for people with chronic kidney disease or who are on dialysis.

calcium test is almost always ordered along with a PTH test. It is not just the level in the blood that is important but the balance between calcium and PTH and the response of the parathyroid glands to changing levels of calcium. Usually, health practitioners are concerned about either severe imbalances in calcium regulation that may require medical intervention or persistent imbalances that indicate an underlying problem.

PTH levels can be used to monitor people who have conditions or diseases that cause chronic calcium imbalances or to monitor those who have had surgery or another treatment for a parathyroid tumor.